The association of factor V Leiden with myocardial infarction is replicated in 1880 patients with premature disease

Acute Myocardial Infarction in Patients with Hereditary Thrombophilia-A Focus on Factor V Leiden and Prothrombin G20210A

Factor V (FV) Leiden and prothrombin G20210A are the most common hereditary thrombophilias. While their role in venous thromboembolism is well known, there are still uncertainties regarding their relationship with arterial thrombotic events, especially coronary ones. Our research, based on an in-depth analysis of the available literature, provides up-to-date information on the relationship between FV Leiden and prothrombin G20210A and acute myocardial infarction. FV Leiden and prothrombin G20210A screening should be implemented only in select cases, such as acute coronary syndrome in young individuals and/or in the absence of traditional cardiovascular risk factors and/or in the absence of significant coronary artery stenosis at angiography. Their identification should be followed by the implementation of optimal control of modifiable traditional cardiovascular risk factors to reduce the risk of recurrent events and genotyping and genetic counseling of all family members of affected cases for proper prophylaxis. An extended dual antiplatelet therapy (DAPT) may be considered, given the lower risk of bleeding under DAPT conferred by FV Leiden.

Dilemmas in hematology: consults in patients with arterial thrombosis

Arterial thrombotic events, particularly ischemic stroke and myocardial infarction, are common, and mostly occur due to atherosclerotic disease or arrhythmias. The diagnosis and management of the majority of such events occurs without the involvement of a hematologist, following established guidelines or pathways. In this review, we discuss 3 scenarios in which optimal management is less certain. These scenarios concern patients with a left ventricular thrombus, in whom the duration and choice of anticoagulant has been debated, patients with ischemic stroke and a patent foramen ovale, in whom the role of patent foramen ovale closure requires careful consideration, and the role of thrombophilia testing in young patients after a stroke or myocardial infarction, which remains an area of contention. We consider the available evidence and published guidelines in order to provide a practical, evidence-based approach to these 3 clinical scenarios.

Factor V Leiden but not the factor II 20210G>A mutation is a risk factor for premature coronary artery disease: a case-control study in Iran

Background

Factor V Leiden (FVL) and factor II c.∗97G>A (rs1799963) are genetic risk factors for venous thromboembolism. Their contribution to coronary artery disease (CAD) is less clear.

Objectives

This study aimed to investigate the association between FVL, rs1799963, and premature CAD in Iranians.

Methods

We performed a genetic case-control study of 944 cases and 1081 controls from the premature CAD Milano-Iran study, including patients aged 18-55 (female) and 18-45 years (male) who underwent coronary angiography at the Tehran Heart Centre (Iran) in 2004-2011. Cases had luminal stenosis ≥50% in at least 1 main coronary artery or branch. Controls were age- and sex-matched with no CAD history. FVL and rs1799963 were genotyped using TaqMan SNP genotyping assays. Association was tested by logistic regression adjusted for matching factors and ethnicity. Effect modification by sex and cardiovascular risk factors (metabolic [obesity, hypertension, hyperlipidemia, and diabetes], and smoking) was assessed.

Results

The risk of premature CAD was increased by 50% in FVL carriers (adjusted odds ratio [adjOR] 1.54 [95% CI, 0.95-2.48]) and slightly reduced in rs1799963 carriers (adjOR 0.71 [95% CI, 0.40-1.27]). These effects were more pronounced in women than men (FVL, adjOR 1.66 vs 1.25; rs1799963, adjOR 0.60 vs 1.07). The risk of premature CAD was substantially increased in carriers of FVL with at least 1 metabolic risk factor compared with noncarriers without metabolic risk factors (adjOR 25.14 [95% CI, 12.51-50.52]).

Conclusion

FVL but not FII rs1799963 was associated with an increased risk of CAD in young Iranians. This risk increased considerably when combined with metabolic cardiovascular risk factors.

Risk factors profile of young and older patients with myocardial infarction

Myocardial infarction (MI) among young adults (<45 years) represents a considerable proportion of the total heart attack incidents. The underlying pathophysiologic characteristics, atherosclerotic plaque features, and risk factors profile differ between young and older patients with MI. This review article discusses the main differences between the younger and elderly MI patients as well as the different pathogenic mechanisms underlying the development of MI in the younger. Young patients with MI often have eccentric atherosclerotic plaques with inflammatory features but fewer lesions, and are more likely to be smokers, obese, and have poor lifestyle, such as inactivity and alcohol intake. Compared to older MI patients, younger are more likely to be men, have familial-combined hyperlipidaemia and increased levels of lipoprotein-a. In addition, MI in younger patients may be related to use of cannabis, cocaine use, and androgenic anabolic steroids. Genomic differences especially in the pathways of coagulation and lipid metabolism have also been identified between young and older patients with MI. Better understanding of the risk factors and the anatomic and pathophysiologic processes in young adults can improve MI prevention and treatment strategies in this patient group. Awareness could help identify young subjects at increased risk and guide primary prevention strategies. Additional studies focusing on gene pathways related to lipid metabolism, inflammation, and coagulation are needed.

Causes, Angiographic Characteristics, and Management of Premature Myocardial Infarction: JACC State-of-the-Art Review

Among patients presenting with acute myocardial infarction (AMI), the proportion of young individuals has increased in recent years. Although coronary atherosclerosis is less extensive in young patients with AMI, with higher prevalence of single-vessel disease and rare left main involvement, the long-term prognosis is not benign. Young patients with AMI with obstructive coronary artery disease have similar risk factors as older patients except for higher prevalence of smoking, lipid disorders, and family history of premature coronary artery disease, and lower prevalence of diabetes mellitus and hypertension. Smoking cessation is by far the most effective secondary preventive measure. Myocardial infarction with nonobstructive coronary arteries is a relatively common clinical entity (10%-20%) among young patients with AMI, with intravascular and cardiac magnetic resonance imaging being key for diagnosis and potentially treatment. Spontaneous coronary artery dissection is a frequent pathogenetic mechanism of AMI among young women, requiring a high degree of suspicion, especially in the peripartum period.

Factor V Leiden and the Risk of Bleeding in Patients With Acute Coronary Syndromes Treated With Antiplatelet Therapy: Pooled Analysis of 3 Randomized Clinical Trials

Background

Whether factor V Leiden is associated with lower bleeding risk in patients with acute coronary syndromes using (dual) antiplatelet therapy has yet to be investigated.

Methods and Results

We pooled data from 3 randomized clinical trials, conducted in patients with acute coronary syndromes, with adjudicated bleeding outcomes. Cox regression models were used to obtain overall and cause‐specific hazard ratios (HRs) to account for competing risk of atherothrombotic outcomes (ie, composite of ischemic stroke, myocardial infarction, and cardiovascular death) in each study. Estimates from the individual studies were pooled using fixed effect meta‐analysis. The 3 studies combined included 17 623 patients of whom 969 (5.5%) were either heterozygous or homozygous (n=23) carriers of factor V Leiden. During 1 year of follow‐up, a total of 1289 (7.3%) patients developed major (n=559) or minor bleeding. Factor V Leiden was associated with a lower risk of combined major and minor bleeding (adjusted cause‐specific HR, 0.75; 95% CI, 0.56–1.00; P=0.046; I²=0%) but a comparable risk of major bleeding (adjusted cause‐specific HR, 0.93; 95% CI, 0.62–1.39; P=0.73; I²=0%). Adjusted pooled cause‐specific HRs for the association of factor V Leiden with atherothrombotic events alone and in combination with bleeding events were 0.75 (95% CI, 0.55–1.02; P=0.06; I²=0%) and 0.75 (95% CI, 0.61–0.92; P=0.007; I²=0%), respectively.

Conclusions

Given that the lower risk of bleeding conferred by factor V Leiden was not counterbalanced by a higher risk of atherothrombotic events, these findings warrant future assessment for personalized medicine such as selecting patients for extended or intensive antiplatelet therapy.

How I treat unexplained arterial thrombosis

Most arterial thrombotic events have a clear atherosclerotic or cardioembolic etiology, but hematologists are frequently asked to assist in the diagnosis and management of a patient with a nonatherosclerotic and noncardioembolic arterial event, referred to here as an unexplained arterial thrombosis. Because there is an assorted list of factors that can precipitate an arterial event, we present a systematic diagnostic approach to ensure consideration of not only primary hypercoagulable disorders, but also pro-thrombotic medications or substances, vascular and anatomic abnormalities, and undiagnosed systemic disorders, such as malignancy and autoimmune diseases. We also review existing literature of the role of hypercoagulable disorders in arterial thrombosis and discuss our approach to thrombophilia workup in patients after an unexplained arterial event. We conclude with 3 representative cases to both illustrate the application of the outlined diagnostic schema and discuss common management considerations, specifically the selection of anticoagulation vs antiplatelet therapy for secondary prevention.

Association of venous thromboembolism and myocardial infarction with Factor V Leiden and Factor II gene mutations among Libyan patients

Factor V Leiden G1691A (FVL) and Factor II prothrombin G20210A (PGM) mutations are the leading causes of thrombophilia. In this study, we have investigated the prevalence of the FVL G1691A and PGM G20210A single nucleotide polymorphisms (SNPs) among Libyan deep vein thrombosis (DVT) and myocardial infarction (MI) patients. SNP genotyping was performed using high-resolution melt analysis (HRM) and DNA sequencing. Biochemical parameters conducted on 112 males and 93 females showed no significant difference in means between the control group and the deep vein thrombosis and myocardial infarction groups. For Factor V Leiden, 40 samples were genotyped. Of the 40 samples, 6 (15.0%) of them were heterozygous and no one was homozygous. As for Factor II SNP, 59 samples were genotyped and only 2 (3.3%) were heterozygous. All the heterozygous samples showed 100% concordance between the HRM-PCR and DNA sequence analysis. Our study showed, for the first time, that both the FVL and PGM mutations are present among Libyan DVT and MI patients and that the FVL mutation is significantly associated with DVT but not with MI. However, our results do not support the association of PGM G20210A mutation with DVT or MI.

Myocardial Infarction Without Obstructive Coronary Artery Disease (MINOCA): A Practical Guide for Clinicians

Myocardial infarction without obstructive coronary artery disease (MINOCA) is defined by the evidence of spontaneous acute myocardial infarction (MI) and angiographic exclusion of coronary stenoses ≥50% in any potential infarct related artery, after having ruled out other clinically overt causes for the acute presentation. The introduction of this new concept was meant to encourage discovery of putative pathophysiological mechanisms and development of specific therapeutic measures. In recent years, we have witnessed significant advances in the fields of epidemiology, pathophysiology, diagnosis, prognosis estimation and therapeutics of MINOCA. So far, however, the definition of MINOCA has been rather heterogeneous since specific cardiac conditions such as myocarditis and Takotsubo syndrome have often been included, generating conflicting results. In this review, we summarize the current state-of-the-art in the expanding MINOCA field and propose a comprehensive stepwise approach for the rational diagnostic assessment of these challenging patients. Our aim is to provide clinicians with an "Ariadne's thread" according to the recent fourth universal definition of MI in order to not get lost in MINOCA's labyrinth.

Association of Factor V Leiden With Subsequent Atherothrombotic Events: A GENIUS-CHD Study of Individual Participant Data

BACKGROUND

Studies examining the role of factor V Leiden among patients at higher risk of atherothrombotic events, such as those with established coronary heart disease (CHD), are lacking. Given that coagulation is involved in the thrombus formation stage on atherosclerotic plaque rupture, we hypothesized that factor V Leiden may be a stronger risk factor for atherothrombotic events in patients with established CHD.

METHODS

We performed an individual-level meta-analysis including 25 prospective studies (18 cohorts, 3 case-cohorts, 4 randomized trials) from the GENIUS-CHD (Genetics of Subsequent Coronary Heart Disease) consortium involving patients with established CHD at baseline. Participating studies genotyped factor V Leiden status and shared risk estimates for the outcomes of interest using a centrally developed statistical code with harmonized definitions across studies. Cox proportional hazards regression models were used to obtain age- and sex-adjusted estimates. The obtained estimates were pooled using fixed-effect meta-analysis. The primary outcome was composite of myocardial infarction and CHD death. Secondary outcomes included any stroke, ischemic stroke, coronary revascularization, cardiovascular mortality, and all-cause mortality.

RESULTS

The studies included 69 681 individuals of whom 3190 (4.6%) were either heterozygous or homozygous (n=47) carriers of factor V Leiden. Median follow-up per study ranged from 1.0 to 10.6 years. A total of 20 studies with 61 147 participants and 6849 events contributed to analyses of the primary outcome. Factor V Leiden was not associated with the combined outcome of myocardial infarction and CHD death (hazard ratio, 1.03 [95% CI, 0.92-1.16]; I2=28%; P-heterogeneity=0.12). Subgroup analysis according to baseline characteristics or strata of traditional cardiovascular risk factors did not show relevant differences. Similarly, risk estimates for the secondary outcomes including stroke, coronary revascularization, cardiovascular mortality, and all-cause mortality were also close to identity.

CONCLUSIONS

Factor V Leiden was not associated with increased risk of subsequent atherothrombotic events and mortality in high-risk participants with established and treated CHD. Routine assessment of factor V Leiden status is unlikely to improve atherothrombotic events risk stratification in this population.

Application of Genome-Wide Association Studies in Coronary Artery Disease

Coronary artery disease (CAD) is a complex disease caused by the combination of environmental and genetic factors. It is one of the leading causes of death and disability in the world. Much research has been focussed on CAD genetic mechanism. In recent years, genome-wide association study (GWAS) has developed rapidly around the world. Medical researchers around the world have successfully discovered a series of CAD genetic susceptibility genes or susceptible loci using medical research strategies, leading CAD research toward a new stage. This paper briefly summarizes the important progress made by GWAS for CAD in the world in recent years, and then analyzes the challenges faced by GWAS at this stage and the development trend of future research, to promote the transformation of genetic research results into clinical practice and provide guidance for further exploration of the genetic mechanism of CAD.

Acute myocardial infarction in adolescents: reappraisal of underlying mechanisms

Worldwide, a myocardial infarction (MI) is an important cause of death. Acute MI occurs most commonly at an older age. However, the incidence of acute MI in adolescents is increasing. This is partly due to an increase in cardiovascular risk factors (e.g. smoking, unhealthy diet), which might lead to premature atherosclerosis. However, several non-atherosclerotic causes of MI in adolescents are also described in the literature, such as vascular spasm due to the use of cocaine. We may assume that acute MI is not considered to be the most likely cause of chest pain in adolescents. Therefore, the risk of a dramatic outcome in this patient category may be significant. This point of view article addresses the pathophysiological process and subsequent diagnostic approach in adolescents with MI resulting from either premature atherosclerosis or of non-atherosclerotic causes. Insight into the potential operational mechanisms of the coronary artery incident may have a major impact on the clinical course following admission. We would like to underline that a personalised clinical approach remains of utmost importance in each patient treated by protocolised medicine. This is particularly true when acute MI occurs at a young age, since the underlying cause more frequently differs from the conventional atherosclerotic process in this patient category.

High prevalence of inherited thrombophilia and antiphospholipid syndrome in myocardial infarction with non-obstructive coronary arteries: Comparison with cryptogenic stroke

BACKGROUND

A role of thrombophilia in myocardial infarction with non-obstructive coronary arteries (MINOCA) is unclear. We investigated thrombophilic factors in MINOCA patients versus those following cryptogenic stroke (CS), a well-established indication for thrombophilia screening.

METHODS

In a prospective cross-sectional study, we assessed 84 consecutive patients (median age: 45.5 years) at least 3 months after MINOCA. Age-matched CS patients (n = 84) and published data on general population served as controls. Thrombophilia screening involved inherited thrombophilia (factor V Leiden, prothrombin G20210A mutation, deficiency of protein C, protein S or antithrombin), antiphospholipid syndrome (APS), along with factor VIII >150%, homocysteine ≥15 μM and lipoprotein (a) >30 mg/dl.

RESULTS

Compared to CS, MINOCA were more often males (60.7 vs 33.3%, P < 0.001), obese (34.5 vs 17.9%, P = 0.014), smokers (51.2 vs 35.7%, P = 0.043) and had family history of myocardial infarction (27.4 vs 6.0%, P < 0.001). Inherited thrombophilia occurred in 20 (23.8%) MINOCA patients and in 13 (15.5%) with CS (P = 0.17), without any difference in the parameters except for elevated lipoprotein (a) that was less common in MINOCA (21.4 vs 39.3%, P = 0.012). APS was found in 13 (15.5%) of MINOCA patients, mostly in a single-positive form. APS was diagnosed less frequently in STEMI (2.5 vs 27.3% for NSTEMI, P = 0.002) and MINOCA patients aged ≤50 years (5.7 vs 32.3% for older subjects, P = 0.003).

CONCLUSIONS

MINOCA patients exhibit high prevalence of thrombophilia including APS, similar to that in CS. Our first comprehensive thrombophilia testing in MINOCA supports its clinical relevance and the need for long-term anticoagulation for some abnormalities, especially APS.

Contemporary Diagnosis and Management of Patients With Myocardial Infarction in the Absence of Obstructive Coronary Artery Disease: A Scientific Statement From the American Heart Association

Myocardial infarction in the absence of obstructive coronary artery disease is found in ≈5% to 6% of all patients with acute infarction who are referred for coronary angiography. There are a variety of causes that can result in this clinical condition. As such, it is important that patients are appropriately diagnosed and an evaluation to uncover the correct cause is performed so that, when possible, specific therapies to treat the underlying cause can be prescribed. This statement provides a formal and updated definition for the broadly labelled term MINOCA (incorporating the definition of acute myocardial infarction from the newly released “Fourth Universal Definition of Myocardial Infarction”) and provides a clinically useful framework and algorithms for the diagnostic evaluation and management of patients with myocardial infarction in the absence of obstructive coronary artery disease.

Prothrombin G20210A (rs1799963) polymorphism increases myocardial infarction risk in an age-related manner: A systematic review and meta-analysis

G20210A polymorphism (rs1799963) within the prothrombin gene is associated with a higher circulation level of prothrombin, thus increasing the likelihood of developing myocardial infarction (MI). Opinions differ regarding the correlation between prothrombin G20210A genotype and MI risk, which prompted us to conduct a meta-analysis to determine this association. PubMed, EMBASE, Web of Science and CNKI were searched for pertinent reports. A total of 34 studies involving 14 611 MI cases and 84 358 controls were analyzed in this quantitative analysis. We found a statistically significant association between prothrombin G20210A polymorphism and MI in the allele model (A vs. G, OR = 1.43, 95%CI: 1.18–1.72), heterozygote model (GA vs. GG, OR = 1.41, 95%CI: 1.16–1.72) and dominant model (GA + AA vs. GG, OR = 1.41, 95%CI: 1.15–1.72). The association remains significant in Caucasians but not in non-Caucasians. Moreover, prothrombin G20210A polymorphism increases MI risk in an age-related manner. A further significant association was found in a subpopulation younger than 55 years (allele model, OR = 1.76, 95%CI: 1.32–2.35; heterozygote model, OR = 1.70, 95%CI: 1.24–2.33; dominant model, OR = 1.70, 95%CI: 1.24–2.34). Sensitivity analysis and publication bias analysis revealed stable and statistically robust results. Our meta-analysis demonstrated that prothrombin G20210A polymorphism may represent a risk factor for MI.

G2691A and C2491T mutations of factor V gene and pre-disposition to myocardial infarction in Morocco

Coagulation factor Leiden mutation has been described as a common genetic risk factor for venous thrombosis; however, this mutation was reported to be practically absent in an African population. Recently, a novel non-sense mutation in the gene encoding factor V has been associated with the risk of occurrence of cardio-cerebrovascular diseases such as stroke and venous thrombosis. The aim of the present study was to investigate whether the factor V Leiden (FVL) and C2491T non-sense mutations are associated with the risk of developing myocardial infarction. Genotyping of FVL and C2491T FV was performed using the polymerase chain reaction restriction fragment length polymorphism method on a sample of 100 patients with myocardial infarction as well as 211 controls. In the study population, the frequency of the FVL mutation was practically zero. However, with regard to the C2491T mutation, the TT genotype was associated with an increased risk of myocardial infarction [odds ratio (OR)=3.16, 95% confidence interval (CI): 1.29-7.71, P=0.03]. A significant association between the C2491T FV mutation and the risk of myocardial infarction was identified using recessive (OR=2.74, 95% CI: 1.14-6.58, P=0.04), dominant (OR=1.85, 95% CI: 1.13-3.04, P=0.02) and additive (OR=1.88, 95% CI: 1.25-2.80, P=0.004) models. Furthermore, a positive correlation was found between the presence of the C2491T FV mutation and hypertension (P=0.02), which is associated with myocardial infarction. In conclusion, the results of the present study suggested that the C2491T non-sense mutation of the FV gene may be a risk factor for myocardial infarction in a Moroccan population.

Skin Necrosis in a Patient with Factor V Leiden Mutation following Nipple Sparing Mastectomy

Nipple-sparing mastectomy (NSM) and immediate breast reconstruction have replaced radical surgical interventions for the treatment of selected patients with breast cancer undergoing prophylactic mastectomy. NSM is technically a difficult procedure. After dissection, the remaining breast skin and nipple-areola complex (NAC) must be thin enough to be free of tumor tissue and thick enough to preserve tissue perfusion. Factor V Leiden mutation is the most common cause of hereditary thrombophilia; thrombosis almost always develops in the venous system. The literature includes only a few case series of arterial thrombosis. The present study aimed to describe for the first time a patient with Factor V Leiden mutation that developed nipple-areola complex and skin necrosis, and multiple embolisms in the upper extremity arteries following NSM.

Systems analysis of gene ontology and biological pathways involved in post-myocardial infarction responses

Background

Pathway analysis has been widely used to gain insight into essential mechanisms of the response to myocardial infarction (MI). Currently, there exist multiple pathway databases that organize molecular datasets and manually curate pathway maps for biological interpretation at varying forms of organization. However, inconsistencies among different databases in pathway descriptions, frequently due to conflicting results in the literature, can generate incorrect interpretations. Furthermore, although pathway analysis software provides detailed images of interactions among molecules, it does not exhibit how pathways interact with one another or with other biological processes under specific conditions.

Methods

We propose a novel method to standardize descriptions of enriched pathways for a set of genes/proteins using Gene Ontology terms. We used this method to examine the relationships among pathways and biological processes for a set of condition-specific genes/proteins, represented as a functional biological pathway-process network. We applied this algorithm to a set of 613 MI-specific proteins we previously identified.

Results

A total of 96 pathways from Biocarta, KEGG, and Reactome, and 448 Gene Ontology Biological Processes were enriched with these 613 proteins. The pathways were represented as Boolean functions of biological processes, delivering an interactive scheme to organize enriched information with an emphasis on involvement of biological processes in pathways. We extracted a network focusing on MI to demonstrate that tyrosine phosphorylation of Signal Transducer and Activator of Transcription (STAT) protein, positive regulation of collagen metabolic process, coagulation, and positive/negative regulation of blood coagulation have immediate impacts on the MI response.

Conclusions

Our method organized biological processes and pathways in an unbiased approach to provide an intuitive way to identify biological properties of pathways under specific conditions. Pathways from different databases have similar descriptions yet diverse biological processes, indicating variation in their ability to share similar functional characteristics. The coverages of pathways can be expanded with the incorporation of more biological processes, predicting involvement of protein members in pathways. Further, detailed analyses of the functional biological pathway-process network will allow researchers and scientists to explore critical routes in biological systems in the progression of disease.

Association of seven thrombotic pathway gene CpG-SNPs with coronary heart disease

OBJECTIVES

Coronary heart disease (CHD) has been considered a thromboembolic arterial diseases. The aim of this case-control study was to explore whether the CpG-SNPs of the thrombotic pathway genes contributed to the risk of CHD.

METHODS AND MATERIALS

A total of 784 CHD patients and 738 healthy controls were recruited in the current association study, which evaluated 7 CpG-SNPs of the thrombotic pathway genes. The CpG-SNPs included THBS4 rs17878919, CYP2C19 rs12773342, P2RY12 rs1491974, ITGA2 rs26680, FGB rs2227389, F7 rs510317 and F5 rs2269648. SNP genotyping was performed with a Sequenom Mass Spectrometry Genetic Analyzer.

RESULTS

Our results demonstrated that CYP2C19 rs12773342 polymorphism was significantly associated with CHD in the recessive model (χ(2)=5.41, df=1, P=0.020, OR=1.455, 95% CI=1.060-1.996). A breakdown analysis by age showed that the association of CYP2C19 rs12773342 with CHD was mainly found in individuals aged 55-65 (genotype: χ(2)=7.93, df=2, P=0.019; allele: χ(2)=4.45, df=1, P=0.035). In addition, we also observed a significant association between F7 rs510317 polymorphism and CHD in males (genotype: χ(2)=7.24, df=2, P=0.027). There was no significant association with CHD for the remaining CpG-SNPs.

CONCLUSION

Our results supported that the CYP2C19 rs12773342 and F7 rs510317 polymorphisms were associated with CHD in the Han Chinese population.

Gender Specificity of a Genetic Variant of Androgen Receptor and Risk of Coronary Artery Disease

BACKGROUND

Androgens are known to influence the risk of developing cardiovascular diseases. This study aims at investigating the possible association between G1733A polymorphism in the coding region of androgen receptor (AR) gene and premature coronary artery disease (CAD).

METHODS

A total of 460 Greek subjects were investigated for the G1733A polymorphism. The patient group consisted of 250 CAD individuals, aged less than 58 years, while 210 healthy individuals served as controls. Genotyping was performed using the PCR-RFLP method.

RESULTS

Significant differences in genotype distribution (P = 0.0067) and allele frequencies (P = 0.0060) have been observed between patients and controls in the women's subgroup. Conversely, the genotype/allele frequencies were similar between patients and controls in the subgroup of men.

CONCLUSION

We may conclude that the G1733A polymorphism of AR gene could be a useful genetic marker for the assessment of a woman's risk for CAD in our Caucasian Greek population.

Association of Hemostatic Gene Polymorphisms With Early-Onset Ischemic Heart Disease in Egyptian Patients

The association between hereditary thrombophilia and venous thrombosis is well established but controversial data exist with respect to arterial thrombosis. We performed a pilot study on 31 patients with acute myocardial infarction (AMI), 21 patients with unstable angina (UA), and 20 healthy volunteers to investigate the role of various hemostatic gene polymorphisms in young Egyptian patients, who survived their first ischemic heart disease (IHD). Thrombophilic gene polymorphisms were tested using multiplex polymerase chain reaction and reverse-hybridization technique. We showed an increased risk of AMI with factor V (FV) Leiden and prothrombin G20210A heterozygosity. The increased risks of UA was associated with GA and A allele of fibrinogen β-455G→A polymorphism. Conversely, factor XIII (FXIII) Val34Leu GT and T allele were protective in the UA group. Nevertheless, the prevalence of FV H1299R, plasminogen activator inhibitor 1 4G/5G, glycoprotein IIIa C1565T, 5,10-methylenetetrahydrofolate reductase C677T, and A1298C mutations did not differ between patients with IHD and controls. The data have clinical implications regarding screening and thromboprophylaxis in high-risk individuals younger than 40 years.

Testosterone therapy and cardiovascular risk

Endogenous testosterone levels are inversely associated with cardiovascular risk in older men and men with cardiovascular disease. Current data on cardiovascular outcomes of testosterone therapy include only observational studies and adverse event monitoring in short-term trials that were not designed to measure cardiovascular outcomes. These studies have yielded conflicting results, and some have raised concerns that testosterone therapy may increase cardiovascular risk. A well-designed, adequately powered, prospective trial will ultimately be required to clarify whether testosterone therapy impacts cardiovascular outcomes. This review describes the findings and limitations of recent studies of cardiovascular risk in older men on testosterone therapy and discusses some of the mechanisms through which testosterone may modify cardiovascular risk.

Individuals with coronary artery disease at a young age and features of the metabolic syndrome have an increased prothrombotic potential

The relation between coagulation and atherosclerosis has been extensively described, pointing towards a hypercoagulable state in patients with atherosclerosis, especially in young individuals. However, not all studies were conclusive. It is known that the metabolic syndrome (MetS), a risk factor for coronary artery disease (CAD), is related to a higher incidence of thrombo-embolic events. We hypothesised that individuals with CAD at a young age and MetS have an increased prothrombotic potential. It was the study objective to analyse the endogenous thrombin potential (ETP) and related thrombin generation parameters in patients with CAD before the age of 51 in men and 56 in women with and without MetS features and their healthy first-degree relatives. In this case-control study we included 118 CAD patients and 50 first-degree relatives (controls). Parameters of thrombin generation were obtained with calibrated automated thrombinography. An adjusted general linear model (GLM) showed a positive association between the peak thrombin levels and the presence of CAD at a young age. Based on the NCEP criteria we divided our patient group in CAD patients with and without MetS, and compared them to the controls without MetS. We showed that CAD patients with MetS have increased ETP levels, both in comparison with healthy first-degree relatives and with CAD patients without MetS. There were no differences in ETP between patients without MetS and healthy controls. In conclusion, this study shows that individuals with CAD at a young age and MetS features have an increased prothrombotic potential, compared to CAD patients without MetS.

Prothrombotic gene variants as risk factors of acute myocardial infarction in young women

Background

Acute myocardial infarction (AMI) in young women represent an extreme phenotype associated with a higher mortality compared with similarly aged men. Prothrombotic gene variants could play a role as risk factors for AMI at young age.

Methods

We studied Factor V Leiden, FII G20210A, MTHFR C677T and beta-fibrinogen -455G>A variants by real-time PCR in 955 young AMI (362 females) and in 698 AMI (245 females) patients. The data were compared to those obtained in 909 unrelated subjects (458 females) from the general population of the same geographical area (southern Italy).

Results

In young AMI females, the allelic frequency of either FV Leiden and of FII G20210A was significantly higher versus the general population (O.R.: 3.67 for FV Leiden and O.R.: 3.84 for FII G20210A; p<0.001). Among AMI patients we showed only in males that the allelic frequency of the MTHFR C677T variant was significantly higher as compared to the general population. Such difference was due to a significantly higher frequency in AMI males of the MTHFR C677T variant homozygous genotype (O.R. 3.05).

Discussion and conclusion

Our data confirm that young AMI in females is a peculiar phenotype with specific risk factors as the increased plasma procoagulant activity of FV and FII. On the contrary, the homozygous state for the 677T MTHFR variant may cause increased levels of homocysteine and/or an altered folate status and thus an increased risk for AMI, particularly in males. The knowledge of such risk factors (that may be easily identified by molecular analysis) may help to improve prevention strategies for acute coronary diseases in specific risk-group subjects.

Acute coronary events

In the United States alone, more than 400,000 Americans die annually from coronary artery disease and more than 1,000,000 suffer acute coronary events, i.e., myocardial infarction and sudden cardiac death.1 Considering the aging of our population and increasing incidence of diabetes and obesity, the morbidity from coronary artery disease, and its associated costs, will place an increasing, substantial burden on our society.2 Between 2010 and 2030, total direct medical costs spent in the US for cardiovascular diseases are projected to triple from 273 to 818 billion dollars.2 Although effective treatments are available and considerable efforts are ongoing to identify new strategies for the prevention of coronary events, predicting such events in an individual has been challenging.3 In hopes of improving our ability to determine the risk of coronary events, it is prudent to review our knowledge of factors that lead to acute coronary events.

Free protein S level as a risk factor for coronary heart disease and stroke in a prospective cohort study of healthy United Kingdom men

Plasma protein S (PS) levels are reportedly low in patients with venous thrombosis but high in coronary heart disease (CHD) patients. The authors examined the association between free PS concentration and CHD or stroke risk and assessed risk in combination with C-reactive protein (CRP) levels. Free PS concentration was determined in 6 annual visits among 3,052 middle-aged (49-64 years) United Kingdom men from the Second Northwick Park Heart Study, with 297 CHD events from 1989 to 2005. The highest (vs. first) quintile was associated with a significantly increased CHD risk after adjustment for all other risk factors and correction for regression dilution bias (hazard ratio = 1.85, 95% confidence interval: 1.08, 3.16; P = 0.024). Models that included all well-known risk factors plus PS quintiles improved prediction of CHD (net reclassification improvement (NRI) = 7.0% (P = 0.007), category-less NRI (>0) = 22.1% (P < 0.001)), and the likelihood ratio statistic increased significantly (P = 0.018). The increase in CHD risk was particularly strong when subjects also had high CRP levels. There was no association between free PS level and stroke risk. This study confirms the independent association of elevated free PS levels with future risk of CHD, although elevated PS levels added only modestly to prediction metrics. The novel finding of increased CHD risk, particularly when CRP and PS levels are high, requires further study.

Common variants in the haemostatic gene pathway contribute to risk of early-onset myocardial infarction in the Italian population

Occlusive coronary thrombus formation superimposed on an atherosclerotic plaque is the ultimate event leading to myocardial infarction (MI). Therefore, haemostatic proteins may represent important players in the pathogenesis of MI. It was the objective of this study to evaluate, in a comprehensive way, the role of haemostatic gene polymorphisms in predisposition to premature MI. A total of 810 single nucleotide polymorphisms (SNPs) in 37 genes were assessed for association with MI in a large cohort (1,670 males, 210 females) of Italian patients who suffered from an MI event before the age of 45, and an equal number of controls. Thirty-eight SNPs selected from the literature were genotyped using the SNPlex technology, whereas genotypes for the remaining 772 SNPs were extracted from a previous genome-wide association study. Genotypes were analysed by a standard case-control analysis corrected for classical cardiovascular risk factors, and by haplotype analysis. A weighted Genetic Risk Score (GRS) was calculated. Evidence for association with MI after covariate correction was found for 35 SNPs in 12 loci: F5, PROS1, F11, ITGA2, F12, F13A1, SERPINE1, PLAT, VWF, THBD, PROCR, and F9. The weighted GRS was constructed by including the top SNP for each of the 12 associated loci. The GRS distribution was significantly different between cases and controls, and subjects in the highest quintile had a 2.69-fold increased risk for MI compared with those in the lowest quintile. Our results suggest that a GRS, based on the combined effect of several risk alleles in different haemostatic genes, is associated with an increased risk of MI.

Delineating the Hemostaseome as an aid to individualize the analysis of the hereditary basis of thrombotic and bleeding disorders

Next-generation sequencing and genome-wide association studies represent powerful tools to identify genetic variants that confer disease risk within populations. On their own, however, they cannot provide insight into how these variants contribute to individual risk for diseases that exhibit complex inheritance, or alternatively confer health in a given individual. Even in the case of well-characterized variants that confer a significant disease risk, more healthy individuals carry the variant, with no apparent ill effect, than those who manifest disease. Access to low-cost genome sequence data promises to provide an unprecedentedly detailed view of the nature of the hereditary component of complex diseases, but requires the large-scale comparison of sequence data from individuals with and without disease to deliver a clinical calibration. The provision of informatics support remains problematic as there are currently no means to interpret the data generated. Here, we initiate this process, a prerequisite for such a study, by narrowing the focus from an entire genome to that of a single biological system. To this end, we examine the 'Hemostaseome,' and more specifically focus on DNA sequence changes pertaining to those human genes known to impact upon hemostasis and thrombosis that can be analyzed coordinately, and on an individual basis, to interrogate how specific combinations of variants act to confer disease predisposition. As a first step, we delineate known members of the Hemostaseome and explore the nature of the genetic variants that may cause disease in individuals whose hemostatic balance has become shifted toward either a prothrombotic or anticoagulant phenotype.